Aggregation of Montmorillonite and Organic Matter in Aqueous Media Containing Artificial Seawater

The dispersion-aggregation behaviors of suspended colloids in rivers and estuaries are affected by the compositions of suspended materials (i.e., clay minerals vs. organic macromolecules) and salinity. Laboratory experiments were conducted to investigate the dispersion and aggregation mechanisms of suspended particles under simulated river and estuarine conditions. The average hydrodynamic diameters of suspended particles (representing degree of aggregation) and zeta potential (representing the electrokinetic properties of suspended colloids and aggregates) were determined for systems containing suspended montmorillonite, humic acid, and/or chitin at the circumneutral pH over a range of salinity (0 - 7.2 psu). The original document contains color images. All DTIC reproductions will be in black and white. Pub. in Geochemical Transactions, v10 n2 p1-11, 2009.